CMBWEBDESIGNS, along with all other e-commerce websites we built are based on the truly awesome opensource Opencart software.
It is both powerful, flexible and user friendly. I could go on and on about this but in all honesty there own website explains it so much better. All i can say is that it comes highly recommended from us.
Check out the full list of features over at : OpenCart
If you have any questions specifically about Opencart, we would be happy to help, or you can use opencarts forums that comes with its own wealth of knowledge.